Starting on May 1st 2017, commissions for all app and in-app content will be reduced from 7% to 2.5% globally. All other content types (music, movies, books, and TV) will remain at the current 7% commission rate in all markets. We will also continue to pay affiliate commissions on Apple Music memberships so there are many ways to earn commissions with the program.

After much uproar and disappointment, Apple has issued the following update.

We’d like to clarify some changes being made to the Affiliate Program. Commissions for all iOS in-app purchases will be reduced from 7% to 2.5% globally, and all other content types (including music, movies, books, paid iOS apps and TV) will remain at the current 7%. For more information on commission rates, please see our Getting Started Guide.

Apple appears to suggest that it never meant to drop the commission rates for App Store purchases; however, it's difficult to get that from the original notification.